two-sum solved

Author: mintheon

two-sum/mintheon.java

@@ -0,0 +1,26 @@
+import java.util.HashMap;
+import java.util.Map;
+
+class Solution {
+  /**
+   공간복잡도: O(n)
+   시간복잡도: O(n)
+   */
+
+  public int[] twoSum(int[] nums, int target) {
+    Map<Integer, Integer> numMap = new HashMap<>();
+
+    for(int i = 0; i < nums.length; i++) {
+      numMap.put(nums[i], i);
+    }
+
+    for(int i = 0; i < nums.length; i++) {
+      int pairNum = target - nums[i];
+      if(numMap.containsKey(pairNum) && numMap.get(pairNum) != i) {
+        return new int[]{i, numMap.get(target - nums[i])};
+      }
+    }
+
+    return new int[2];
+  }
+}